Dietary Fiber and Gut Microbiome Study

Intervention of Specific Dietary Fibers on Dynamics of Individual Gut Microbiota

The purpose of this dietary intervention is to study the effects of several dietary fibers on the gut microbiota at the personal level. Hypothesis 1: Intake of specific dietary fibers improves the blood lipid profile depending on the personal microbiota of the participants.

Hypothesis 2: detailed food intake analysis and continuous monitoring of gut microbiota enables to draw causative interrelationships between food components, bacteria of gut microbiome and health characteristics.

Study Overview

• Status: Completed
• Conditions: Healthy
• Intervention / Treatment: Dietary supplement: Dietary fiber 1; Dietary supplement: Dietary fiber 2; Dietary supplement: Dietary fiber 3; Dietary supplement: Dietary fiber 4

Detailed Description

The study design is a cross-over, pre-post intervention trial. All participants are enrolled into all study periods. Study consists of baseline period, four periods of dietary fiber intervention and four periods of wash-outs.

The main goal of this study was to elucidate the patterns between individual dietary fibers and gut microbiota at the personal level. Each person has a unique (individual) intestinal microbiological profile that changes according to lifestyle (diet, environment, physical activity), age and health status. With next generation sequencing methods to map microbial communities and detailed nutritional analysis including blood tests, it is possible to identify the specific effects of specific fiber on a selected (individual) microbiota. TFTAK researchers have long-term experience in microbiota analysis as well as diet design and nutrition analysis, which can be successfully applied in this project.

PRELIMINARY STUDY EVALUATION AND TESTING

1. Complete preliminary study questionnaire
2. Complete orientation to the study and provide voluntary consent to join the study
3. Collection of coded intervention products, sampling supplies, and instructional materials

1-WEEK QUESTIONNAIRE AND LABORATORY VISIT

1. Record food intake and gastrointestinal function for 7 days 2. Collect health data and provide a 7-day food diary using web-based program Nutridata (tap.nutridata.ee) 3. Provide a stool and blood sample at the laboratory 3-WEEK QUESTIONNAIRE AND

LABORATORY VISITS

1. Record food intake and gastrointestinal symptoms for 7 days
2. Collect health data and provide a 3-day food frequency questionnaire
3. Provide a stool and blood sample at the laboratory BLOOD SAMPLE

ANALYSES

1. Provide the blood sample at the laboratory in the morning in an overnight fasted state.

DIETARY INTERVENTION

Study consists of baseline period, four periods of dietary fiber intervention and four periods of wash-outs:

1. Baseline mapping (health questionnaire, 1 week food diary before sampling of blood and gut microbiota)
2. Dietary fiber 1, 3 weeks, analyses: health questionnaire, 1 week food diary before sampling of blood and gut microbiota
3. Wash-out period, 2 weeks, analyses: health questionnaire, 1 week food diary before sampling of blood and gut microbiota
4. Repeating 3 times periods of 2 and 3. In each dietary fiber period 15 g/day of oat fiber, rye fiber, mix I and mix II of dietary fibers are used as test compounds. Dietary fiber mix I and mix II are inulin, beta-glucan, polydextrose, citrus pectin and psyllium, and beta-glucan, citrus pectin and psyllium, respectively.

• Study Type: Interventional
• Enrollment (Actual): 15
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Estonia
  • Harjumaa
    • Tallinn, Harjumaa, Estonia, 12618
      • Center of Food and Fermentation Technologies

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 20 years to 60 years (ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Age 20-60

  • Normal bowel function
  • Omnivorous diet
  • Ability to provide a signed written informed consent
  • Willing to provide stool and blood specimens over the 22-week study period

Exclusion Criteria:

• Diagnosed history of chronic diseases including coronary heart disease, stroke, cancer, type 1 or 2 diabetes mellitus, inflammatory bowel disease, gastritis, autoimmune disease, or rheumatoid arthritis

  • Medication: statins, blood pressure medications, antidepressants, other prescription medications
  • History of bariatric operation, removal of the gallbladder.
  • Food allergies, lactose intolerance
  • Recent (previous 3 months) use of antibiotics
  • Intake of highly dosed pre- or probiotics 2 weeks prior and during the study
  • Current pregnancy or breastfeeding
  • Volunteers showing previously unrecognized illness will also be excluded
  • Individual unable to give informed consent

Study Plan

How is the study designed?

Design Details

• Primary Purpose: BASIC_SCIENCE
• Allocation: NON_RANDOMIZED
• Interventional Model: CROSSOVER
• Masking: DOUBLE

Number of Arms

9

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
NO_INTERVENTION: Baseline; Collection of baseline data 1 week before intervention
EXPERIMENTAL: Dietary fiber 1; 15 g/day oat fiber 3 weeks intervention At the end of period following analyses are collected: 1 week food diary blood sample microbiome sample gut health questionnaire	Dietary supplement: Dietary fiber 1; Description in the arm description
NO_INTERVENTION: Wash-out 1; 2 weeks At the end of period following analyses are collected: 1 week food diary blood sample microbiome sample gut health questionnaire
EXPERIMENTAL: Dietary fiber 2; 15 g/day dietary fiber mix I 3 weeks intervention At the end of period following analyses are collected: 1 week food diary blood sample microbiome sample gut health questionnaire	Dietary supplement: Dietary fiber 2; Description in the arm description
NO_INTERVENTION: Wash-out 2; 2 weeks At the end of period following analyses are collected: 1 week food diary blood sample microbiome sample gut health questionnaire
EXPERIMENTAL: Dietary fiber 3; 15 g/day dietary fiber 3 3 weeks intervention At the end of period following analyses are collected: 1 week food diary blood sample microbiome sample gut health questionnaire	Dietary supplement: Dietary fiber 3; Description in the arm description
NO_INTERVENTION: Wash-out 3; 2 weeks At the end of period following analyses are collected: 1 week food diary blood sample microbiome sample gut health questionnaire
EXPERIMENTAL: Dietary fiber 4; 15 g/day rye fiber 3 weeks intervention At the end of period following analyses are collected: 1 week food diary blood sample microbiome sample gut health questionnaire	Dietary supplement: Dietary fiber 4; Description in the arm description
NO_INTERVENTION: Wash-out 4; 2 weeks At the end of period following analyses are collected: 1 week food diary blood sample microbiome sample gut health questionnaire

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Evaluation of the intestinal microbiota	Fecal microbiota analysis based on the 16S ribosomal RNA (rRNA) sequencing pre- and post-dietary intervention.	150 days
Evaluation of food consumption data	All foods consumed were collected 1 week before the end of every study period using web-based program (tap.nutridata.ee)	150 days
Evaluation of blood lipid profile	Triglycerides, total cholesterol, HDL-cholesterol, LDL-cholesterol after every intervention and wash-out in plasma (mmol/L).	150 days
Evaluation of blood glucose levels	Fasting glucose pre- and post-dietary intervention in plasma (mmol/L).	150
Evaluation of liver characteristics profile	Uric acid, aspartate aminotransferase (ASAT), alanine aminotransferase (ALAT), gamma-glutamyltransferase (GGT) after every intervention and wash-out in plasma (mmol/L).	150

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Evaluation of the stool form	Stool form will be assessed using a validated 7-point scale called Bristol Stool Form Scale pre- and post-dietary intervention.	150 days
Evaluation of the defecation frequency	Evacuation frequency 7 days before every blood and microbiome sampling.; Evacuation frequency (number of bowel movements per week) pre- and post-dietary intervention.	150
Evaluation of the gastrointestinal symptoms	Frequency and severity of the gastrointestinal symptoms (Constipation, Diarrhea, Bloating, Flatulence, Cramps, Stomach pain). Scale of frequency: Never, Less than 10 times a year, Once a month, Once a week, Every day. Scale of severity: I do not have any gastrointestinal symptoms, Mild (does not disturb), Moderate, Strong (disturbs considerably).	150

Collaborators and Investigators

• Sponsor: Center of Food and Fermentation Technologies
• Investigators: Principal Investigator: Kaarel Adamberg, PhD, Center of Food and Fermentation Technologies

Study record dates

Study Major Dates

• Study Start (ACTUAL): February 1, 2022
• Primary Completion (ACTUAL): June 30, 2022
• Study Completion (ACTUAL): July 31, 2022

Study Registration Dates

• First Submitted: June 15, 2022
• First Submitted That Met QC Criteria: June 15, 2022
• First Posted (ACTUAL): June 21, 2022

Study Record Updates

• Last Update Posted (ACTUAL): February 8, 2023
• Last Update Submitted That Met QC Criteria: February 7, 2023
• Last Verified: February 1, 2023

More Information

Terms related to this study

• Keywords: Gut microbiome; dietary fibers; food diary
• Other Study ID Numbers: RTKU

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Anonymized participant data could be made available for subsequent analysis in the mentioned institution (TFTAK). Data made public will include only aggregates or summaries of the collected data.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No